Unable to instrument classes in the /vendor directory

I was able to get AspectMock to instrument my own classes in my directory but I can not get it to work on classes in the composer `/vendor` directory....

Is this even possible?

I tried adding vendor to my `includePaths` but I get the issue in #112

My bootstrap looks basically like this:
```php
require_once __DIR__.'/../vendor/autoload.php'; // composer autoload

$kernel = \AspectMock\Kernel::getInstance();
$kernel->init([
'debug' => true,
'appDir' => __DIR__.'/..',
'cacheDir' => __DIR__.'/_data/aopcache',
'includePaths' => [
__DIR__.'/../repo'
],
'excludePaths' => [
__DIR__,
]
]);
```

Sample of my test code:
```php
$testDataStr = 'var=1&var=2';
$paypalIPN = test::double(new \PayPal\IPN\PPIPNMessage($testDataStr), [
'getRawData' => ['Returned test double'],
]);
$this->assertTrue($paypalIPN->class->hasMethod('getRawData'));
$testData = $paypalIPN->getRawData();
$paypalIPN->verifyInvoked('getRawData'); // fails
```
fails with:
```Expected PayPal\IPN\PPIPNMessage->getRawData to be invoked but it never occurred. Got:```

**Versions**
php 5.6.30
codeception/aspect-mock:2.0.1 @b7f5c50da89419824102400bb4c71988ec33044f
goaop/framework:2.1.2 @6e2a0fe13c1943db02a67588cfd27692bddaffa5
goaop/parser-reflection:1.4.0 @adfc38fee63014880932ebcc4810871b8e33edc9